Delisting plugins

Plugins seem to be automatically pulled into the plugin listing if they have `gridsome-plugin` keyword in `package.json`, but I found at least 1 plugin that isn't functional in the listing:
https://gridsome.org/plugins/@vroger/transformer-img

Is there some way to remove plugins from the list that aren't useful?
There should also be a way for devs to request being listed again, after they've made changes to their plugin.

Start by tracing how the plugin listing is built from package.json keywords, using the @vroger/transformer-img listing as the concrete example. Define how delisting and a later request to be listed again should work, then verify both flows against the issue's requirements.

Written by the indexing model from the issue text.